How to Build a Lean-to Greenhouse

Far from completed, this is my lean-to greenhouse in its infancy.

A lean-to is a structure that hangs, at an angle, off a side of another structure.

The Barn ToolBox offers some great tips for adding a pole barn-like lean-to:

“Adding a lean-to roof to an existing building is a simple do-it-yourself project.  You don’t need to be an experienced builder, but having some common sense wouldn’t hurt…

Leanto additions are very popular since they are easy to build and more cost effective compared to storage sheds or any other buildings.

On this page you’ll find drawings and free PDF plans to build 8′ wide & 10′ wide lean-to overhangs.

When building lean-to addition, there are few things you need to keep in mind.  You must consider the following:

  • Design lean-to roof per your local building codes.
  • Use right size of rafters and headers.
  • Space rafters either 16″ o.c. (for shingles) or 24″ o.c. (for metal roofing).
  • When attaching ledger board to an existing wall, install proper flashing when required.
  • Place pressure treated posts in ground below frost line or on top of concrete piers.”
  • Check here for the free Pdf Roof Plans

My greenhouse follows this basic premise, except that instead of shingles, I use clear fiberglass for the roof’s covering.  Lowe’s sells corrugated clear plastic; and that is also excellentThis greenhouse is covered with corrugated plastic

I got a late start on my greenhouse; and it is far from completed.  In fact, in order to beat the snow, I had to wrap a completed section in plastic.

Eventually, I want to place windows on all the exterior walls as follows:

File:Victorian lean-to greenhouse in the walled garden at Quex Park - - 1216057.jpg

Following is a peek inside the previous greenhouse

Here is another example of a lean-to greenhouse

File:Walled Garden, Little Malvern Court - - 111342.jpg

Here is another set of plans

Attached greenhouse plans

  • A – 2 pieces of 2×4 lumber 200”, 12 pieces of 2×4 lumber 60” SMALL WALL
  • B – 2 pieces of 2×4 lumber 200” – top end cut at 30º, 12 piece of 2×4 lumber 99 1/4” TALL WALL
  • – 12 pieces of 2×4 lumber 87” long – one end cut at 30º, the other end cut at 60º RAFTERS
  • D – 2 pieces of 2×4 93” – cut at 30º,  2 piece of 74 1/4” – cut at 30º, 2 pieces of 27 1/2” FRONT AND BACK
  • D – 3 pieces of 2×4 lumber 24”, 2 pieces of 2×4 lumber 64 1/4, 4 pieces of 10 1/4” FRONT AND BACK
  • – 2 pieces of 2×4 – 69 1/2”, 2 pieces of 2×4 – 24 1/2”, 1 pieces of 2×4 – 17 1/2” DOOR
  • F – 2 pieces of 2×2 lumber, 2 pieces of 2×2 lumber VENT

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